0:05Skip to 0 minutes and 5 secondsDementia is an umbrella term. And it means that it's something that's progressive, so it gets worse over time. And it's neurodegenerative, which is a medical way of saying your brain cells die. So dementia is any disease where your brain cells die more and more over time. There's lots of different types of dementia. And on one level, they're defined by which bit of the brain is being affected. So different bits of our brain do different things. So if the memory bit of your brain is affected by a disease, your memory will get progressively worse but your other skills will stay OK for some time.

0:42Skip to 0 minutes and 42 secondsIf the back of your brain is affected, that's where we think about vision and where things are in space, then those skills will be affected, but your memory and other skills will stay pretty good. If the front of your brain is affected, your behaviour and your social skills will decline, but your memory might actually be really, really good for some time. So there's lots of different kinds of dementia. They've all got different names. Dementia is just this overarching term that means your brain is declining progressively. By far the most common cause is Alzheimer's disease. Alzheimer's disease one specific form of dementia. And it tends to be a problem that starts with memory.

1:22Skip to 1 minute and 22 secondsAnd over time, one tends to get other things involved, so not just memory, but other bits of thinking. And over time, it becomes more the whole brain, so global cognitive impairment. Probably about 50% or 60% of people have Alzheimer's disease in terms of the whole group of people with dementia. And if you think about the other causes, the next in line, people who develop problems with thinning of their blood vessels, what's called vascular dementia or vascular cognitive impairment. After that is a condition called Lewy body dementia. So that's a condition that looks a bit like Parkinson's disease, but tends to start with dementia rather than starting with changes in movement, slowing of movement that you see in Parkinson's disease.

2:09Skip to 2 minutes and 9 secondsAnd then fourth in line is frontotemporal dementia, so a condition that is less common as you get older. But it is a condition that affects your behaviour and your language and in a younger age group, so under 65, tends to be almost as common as Alzheimer's disease, so one of the more common types. Those four things together probably account for somewhere around 95% of all causes of dementia. And then that 5% is lots of other things, so probably hundreds of other things which are all relatively rare, but can cause this acquired progressive problem in your thinking and behaviour.

What is dementia?

Watch Dr Susie Henley and Dr Jon Rohrer describe what dementia is, how it relates to Alzheimer’s disease, and how these conditions affect the brain.

Dementia is an umbrella term for a number of different diseases that affect the brain in different ways.

Dementia is defined as a disease that is progressive (it gets worse over time), affects more than one aspect of thinking (for example, memory, language, behaviour, visual processing) and is severe enough to affect everyday life.

It’s estimated that there are over 850,000 people with dementia in the UK.

Dementia doesn’t just affect the person with dementia, it affects the people around them; their family and friends.

In this course we cover 4 less common forms of dementia and explore how they help us understand more common forms.

Dementia is becoming increasingly recognised as a priority for health and social care, and for research.

Next we move on to look at familial Alzheimer’s disease, but before that please complete the short survey on the next step to help us understand who’s taking the course.